I can reliably get my sim kids to roll one of the three base game money-related wishes—Swimming in Cash, Living in the Lap of Luxury, or CEO of a Mega-corporation—by having them active when items of a certain worth are sold. Not all items count: I don't have an exhaustive list, but home-grown produce, paintings, gems, and metal do, while fish and seeds do not.
Whether I want those LTWs or not, the "buy something worth at least X" wishes are a convenient way to earn kids some points quickly, so when a toddler ages up to child, I usually have an adult go to the grocery store with an inventory full of produce, queue a bunch of Buy commands, and switch to the kid. (It also works to sell gems and metal directly from the kid's inventory.) The sequence goes like this:
- Adult sells §500 of produce -> kid wishes to buy an item worth at least §100
- Adult sells §1,000 -> kid wishes... §250
- Adult sells §2,000 -> kid wishes... §500 and also rolls one of the three LTWs
- Adult sells §3,000 -> kid wishes... §1,000 and/or to buy a piece of exercise equipment worth at least §750 or §1,000
Other situations where kids often roll LTWs:
- Toddler ages up and has read all three writing and all three painting books -> Illustrious Author (almost always)
- Child's younger sibling is born -> World-renowned Surgeon
- Child eats perfect meal -> Celebrated Five-star Chef (but not Culinary Librarian for some reason)
- Child catches perfect fish -> Perfect Private Aquarium
- Child discovers a star -> Astronaut
- Child reaches level 7 logic -> Chess Legend
- Child reaches level 7 of another skill -> Renaissance Sim
- Child/teen attends concert -> Rock Star
- Child/teen has 5 friends -> Super Popular (almost always rolled for teens, and will trigger again every single time the kid makes a new friend until they're assigned a different wish)
- Teen makes X amount (not sure how much) as self-employed writer -> Professional Author
The other skill-based ones, and most of the career wishes, seem to show up much less often and more randomly, although they still roll occasionally when a child or teen hits a certain level (I think it's usually 7) in one of the involved skills. I don't know as much about how teen wishes work because I've usually picked a LTW for them before too long.
One last wish that I can't be sure about due to an extremely small sample size, but that I still distinctly remember appearing more than once, is that when a child or teen witnesses a house fire put out by firefighters, they will also wish to be a Firefighter Super Hero. That seems undertsandable.
